α-Bi2O3 powders were prepared from nanometer Bi powders through low-temperature oxidation at less than 873.15 K. XRD, SEM, TEM and HRTEM were used to characterize the structure and morphology of Bi powders and Bi2O3 ...α-Bi2O3 powders were prepared from nanometer Bi powders through low-temperature oxidation at less than 873.15 K. XRD, SEM, TEM and HRTEM were used to characterize the structure and morphology of Bi powders and Bi2O3 particles. Kinetic studies on the bismuth oxidation at low-temperatures were carried out by TGA method. The results show that bismuth beads should be reunited and oxidized to become irregular Bi2O3 powders. The bismuth oxidation follows shrinking core model, and its controlling mechanism varies at different reaction time. Within 0-10 min, the kinetics is controlled by chemical reaction, after that it is controlled by O2 diffusion in the solid α-Bi2O3 layer. The apparent activation energy is determined as 55.19 kJ/mol in liquid-phase oxidation.展开更多
In recent years, some important research indicated that the visible-light activity of photocatalysts could be enhanced via incorporating p-block non-metal elements into the lattice. In this paper, we investigated the ...In recent years, some important research indicated that the visible-light activity of photocatalysts could be enhanced via incorporating p-block non-metal elements into the lattice. In this paper, we investigated the electronic structures of pure and different non-metal （C, N, S, F, Cl, and Br） doped α-Bi2O3 using first-principles calculations based on the density functional theory. The band structures, the electronic densities of states, and the effective masses of electrons and holes for doped α-Bi2O3 were obtained and analyzed. The N and S dopings narrowed the band gap and reduced the effective mass of the carriers, which are beneficial for the photocatalytic performance. The theoretical predication was further confirmed by the experimental results.展开更多
Single crystalline Bi2O3 nanosheets have been synthesized by the surfactant assisted solvothermal method, using oleic acid and sodium dodecyl benzene sulfonate （SDBS） as compound surfactants. The thickness of Bi2O3 ...Single crystalline Bi2O3 nanosheets have been synthesized by the surfactant assisted solvothermal method, using oleic acid and sodium dodecyl benzene sulfonate （SDBS） as compound surfactants. The thickness of Bi2O3 nanosheets is 40--70 nm with a monoclinic crystal structure. High-resolution transmission electron microscopy observation reveals that （ 345 ） lattice plane of the single crystal is parallel to the surface of the nanosheets. The cooperative effect of oleic acid encapsulated SDBS is the key to form single crystalline a-Bi2O3 nanosheets with a preferred growth orientation. An obvious blue shift of the single crystalline Bi2O3 nanosheets with a preferred surface （ 34-5 ） is observed due to quantum confinement effects in thickness and optical anisotropy.展开更多
基金Project (2006BAB02B05-04- 01/02) supported by the National Key Technologies R&D Program of China
文摘α-Bi2O3 powders were prepared from nanometer Bi powders through low-temperature oxidation at less than 873.15 K. XRD, SEM, TEM and HRTEM were used to characterize the structure and morphology of Bi powders and Bi2O3 particles. Kinetic studies on the bismuth oxidation at low-temperatures were carried out by TGA method. The results show that bismuth beads should be reunited and oxidized to become irregular Bi2O3 powders. The bismuth oxidation follows shrinking core model, and its controlling mechanism varies at different reaction time. Within 0-10 min, the kinetics is controlled by chemical reaction, after that it is controlled by O2 diffusion in the solid α-Bi2O3 layer. The apparent activation energy is determined as 55.19 kJ/mol in liquid-phase oxidation.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51072012 and 51272015)
文摘In recent years, some important research indicated that the visible-light activity of photocatalysts could be enhanced via incorporating p-block non-metal elements into the lattice. In this paper, we investigated the electronic structures of pure and different non-metal （C, N, S, F, Cl, and Br） doped α-Bi2O3 using first-principles calculations based on the density functional theory. The band structures, the electronic densities of states, and the effective masses of electrons and holes for doped α-Bi2O3 were obtained and analyzed. The N and S dopings narrowed the band gap and reduced the effective mass of the carriers, which are beneficial for the photocatalytic performance. The theoretical predication was further confirmed by the experimental results.
基金supported by the National Natural Science Foundation of China (Grant Nos.50431030 and 50871054)the Outstanding Scholar Supporting Program of NUST
文摘Single crystalline Bi2O3 nanosheets have been synthesized by the surfactant assisted solvothermal method, using oleic acid and sodium dodecyl benzene sulfonate （SDBS） as compound surfactants. The thickness of Bi2O3 nanosheets is 40--70 nm with a monoclinic crystal structure. High-resolution transmission electron microscopy observation reveals that （ 345 ） lattice plane of the single crystal is parallel to the surface of the nanosheets. The cooperative effect of oleic acid encapsulated SDBS is the key to form single crystalline a-Bi2O3 nanosheets with a preferred growth orientation. An obvious blue shift of the single crystalline Bi2O3 nanosheets with a preferred surface （ 34-5 ） is observed due to quantum confinement effects in thickness and optical anisotropy.
